This may be old news to some of you but I've been out of the office for a couple weeks and I came across this as I was clearing out my Inbox. Back on December 19th we released an update to the Windows Server DNS 2000/2003/2008 Management Pack for Operations Manager 2007 that includes a couple high CPU utilization and 'disappearing DNS server' fixes to address some issues that existed in the previous version. If you use the Windows Server DNS 2000/2003/2008 Management Pack for Operations Manager 2007 then I'd definitely recommend upgrading to the newest version. You can get more information and download the newest version at http://www.microsoft.com/downloads/details.aspx?FamilyID=633b718f-5fe8-47d5-a395-8203f8ec354f&displaylang=en&displaylang=en.
J.C. Hornbeck | Manageability Knowledge Engineer